In a race with two pawns each, the order of pushes must be chosen so that the first promotion comes with check and the second wins the enemy queen.
A study by Nikolai Grigoriev (1930). White has pawns on f2 and h2 against Black's a7 and d7, and the black king on a3 is already escorting its a-pawn. Everything depends on which white pawn moves first.